Keep XBoard windows attached on resize

Windows attached to bottom or right are displaced with the size increase.
Their perpendicular dimension is also scaled, to keep their edges at the same
fraction of the main window, unless they stick out. In the latter case the
fraction is clipped to 1, so that edge moves with the full size increase.

diff --git a/xboard.c b/xboard.c
index 8cbcfda..47d99f2 100644 (file)
--- a/xboard.c
+++ b/xboard.c
@@ -273,6 +273,7 @@ void CreateGrid P((void));
 int EventToSquare P((int x, int limit));
 void DrawSquare P((int row, int column, ChessSquare piece, int do_flash));
 void EventProc P((Widget widget, caddr_t unused, XEvent *event));
+void DelayedDrag P((void));
 void MoveTypeInProc P((Widget widget, caddr_t unused, XEvent *event));
 void HandleUserMove P((Widget w, XEvent *event,
                     String *prms, Cardinal *nprms));
@@ -1746,6 +1747,9 @@ InitDrawingSizes (BoardSize boardSize, int flags)
     shellArgs[4].value = shellArgs[2].value = w;
     shellArgs[5].value = shellArgs[3].value = h;
     XtSetValues(shellWidget, &shellArgs[0], 6);
+
+    XSync(xDisplay, False);
+    DelayedDrag();
   }
 
     // [HGM] pieces: tailor piece bitmaps to needs of specific variant
@@ -4649,6 +4653,14 @@ DrawSquare (int row, int column, ChessSquare piece, int do_flash)
     }
 }
 
+double
+Fraction (int x, int start, int stop)
+{
+   double f = ((double) x - start)/(stop - start);
+   if(f > 1.) f = 1.; else if(f < 0.) f = 0.;
+   return f;
+}
+
 static WindowPlacement wpNew;
 
 void
@@ -4662,8 +4674,25 @@ CoDrag (Widget sh, WindowPlacement *wp)
     if(abs(wpMain.y + wpMain.height + frameX + frameY - wp->y) < fudge) touch = 3; else // bottom touch
     if(abs(wp->y + wp->height + frameX + frameY - wpMain.y)    < fudge) touch = 4;      // top touch
     if(!touch ) return; // only windows that touch co-move
+    if(touch < 3 && wpNew.height != wpMain.height) { // left or right and height changed
+       int heightInc = wpNew.height - wpMain.height;
+       double fracTop = Fraction(wp->y, wpMain.y, wpMain.y + wpMain.height + frameX + frameY);
+       double fracBot = Fraction(wp->y + wp->height + frameX + frameY + 1, wpMain.y, wpMain.y + wpMain.height + frameX + frameY);
+       wp->y += fracTop * heightInc;
+       heightInc = (int) (fracBot * heightInc) - (int) (fracTop * heightInc);
+       if(heightInc) XtSetArg(args[j], XtNheight, wp->height + heightInc), j++;
+    } else if(touch > 2 && wpNew.width != wpMain.width) { // top or bottom and width changed
+       int widthInc = wpNew.width - wpMain.width;
+       double fracLeft = Fraction(wp->x, wpMain.x, wpMain.x + wpMain.width + 2*frameX);
+       double fracRght = Fraction(wp->x + wp->width + 2*frameX + 1, wpMain.x, wpMain.x + wpMain.width + 2*frameX);
+       wp->y += fracLeft * widthInc;
+       widthInc = (int) (fracRght * widthInc) - (int) (fracLeft * widthInc);
+       if(widthInc) XtSetArg(args[j], XtNwidth, wp->width + widthInc), j++;
+    }
     wp->x += wpNew.x - wpMain.x;
     wp->y += wpNew.y - wpMain.y;
+    if(touch == 1) wp->x += wpNew.width - wpMain.width; else
+    if(touch == 3) wp->y += wpNew.height - wpMain.height;
     XtSetArg(args[j], XtNx, wp->x); j++;
     XtSetArg(args[j], XtNy, wp->y); j++;
     XtSetValues(sh, args, j);
@@ -4673,12 +4702,14 @@ void
 DragProc ()
 {
        GetActualPlacement(shellWidget, &wpNew);
-       if(wpNew.x == wpMain.x && wpNew.y == wpMain.y) return; // not moved, false alarm
+       if(wpNew.x == wpMain.x && wpNew.y == wpMain.y && // not moved
+          wpNew.width == wpMain.width && wpNew.height == wpMain.height) // not sized
+           return; // false alarm
        if(EngineOutputIsUp()) CoDrag(engineOutputShell, &wpEngineOutput);
        if(MoveHistoryIsUp()) CoDrag(shells[7], &wpMoveHistory);
        if(EvalGraphIsUp()) CoDrag(evalGraphShell, &wpEvalGraph);
        if(GameListIsUp()) CoDrag(gameListShell, &wpGameList);
-       wpMain.x = wpNew.x; wpMain.y = wpNew.y;
+       wpMain = wpNew;
        XDrawPosition(boardWidget, True, NULL);
 }